Example output for query-vcpu-dirty-limit

[Markus Armbruster <armbru@redhat.com>]

query-vcpu-dirty-limit's doc comment has an example, but it shows only
input, no output:

    ##
    # @query-vcpu-dirty-limit:
    #
    # Returns information about virtual CPU dirty page rate limits, if any.
    #
    # Since: 7.1
    #
    # Example:
    #   {"execute": "query-vcpu-dirty-limit"}
    #
    ##

The simplest fix is

    # Example:
    # -> {"execute": "query-vcpu-dirty-limit"}
    # <- {"return": []}

But I'd rather show a non-empty reply here.  I don't want to make one
up, because making up example output tends to result in incorrect
examples.  Could you run the command for me in context where it returns
non-empty output?